16491643 has 4 divisors (see below), whose sum is σ = 18847600. Its totient is φ = 14135688.

The previous prime is 16491623. The next prime is 16491647. The reversal of 16491643 is 34619461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34619461 = 1223 ⋅28307.

It is not a de Polignac number, because 16491643 - 2¹³ = 16483451 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 16491599 and 16491608.

It is not an unprimeable number, because it can be changed into a prime (16491647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1177968 + ... + 1177981.

It is an arithmetic number, because the mean of its divisors is an integer number (4711900).

Almost surely, 2^16491643 is an apocalyptic number.

16491643 is a deficient number, since it is larger than the sum of its proper divisors (2355957).

16491643 is an equidigital number, since it uses as much as digits as its factorization.

16491643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2355956.

The product of its digits is 15552, while the sum is 34.

The square root of 16491643 is about 4060.9903964427. The cubic root of 16491643 is about 254.5391805542.

The spelling of 16491643 in words is "sixteen million, four hundred ninety-one thousand, six hundred forty-three".